Conventional dye-sensitized solar cells as described by Gratzel consist of a transparent conducting substrate such as ITO on glass or plastic, on top of which is a sintered layer of titanium dioxide nanoparticles coated with dye (the anode). A hole carrying electrolyte which typically contains iodide/tri-iodide as the electron (or hole) transfer agent is placed within the pores of and on top of this layer. The solar cell sandwich is completed by putting on top of the electrolyte a catalytic conducting electrode, often made with platinum as the catalyst (the cathode). When light is shone on the cell, the dye is excited and an electron is injected into the titanium dioxide structure. The excited, now positively charged dye oxidises the reduced form of the redox couple in the electrolyte to its oxidised form e.g. iodide goes to tri-iodide. This may now diffuse towards the platinum electrode. When the cell is connected to a load the electrons from the anode pass through the load to the cathode and at the cathode the oxidised form of the redox couple is reduced e.g. tri-iodide to iodide, completing the reaction.
Conventional methods of patterning the mesoporous nano-particulate layer include amongst others extrusion coating, screen printing and gravure printing.
U.S. Pat. No. 7,186,911 discloses a dye sensitised nanoparticulate material which may be deposited by applying a solution of metal oxide nanoparticles onto a substrate using suitable techniques such as extrusion coating, spray coating, screen printing and gravure printing.
U.S. Pat. No. 6,991,958 discloses a method of templating charge-carrier-transporting channel layers. These layers are formed by initially depositing a removable template on the conductive substrate that may include single or multi layers of nanoparticles e.g. polystyrene nanospheres. The layer of first charge-carrier-transporting material e.g. TiO2 is then deposited on the template using techniques such as spin coating, casting, evaporation or any other technique known in the art for depositing a material on a substrate. The template is then removed.
U.S. Pat. No. 6,713,389 discloses a method of using a droplet deposition technique and a continuous inkjet printhead (and electrostatic spray head) to eject droplets of an array of custom fluids that when suitably dried/solidified on a specific surface form the elements of a solar cell (PV) device. Materials used in this process may include metallo-organics such as TiO2.
GB 2427963 discloses a dye sensitised solar cell comprising a first patterned transparent conducting electrode with alternate sections of a second electrode layer and metal oxide dye sensitised layer. In this application, the patterned transparent electrode layer (e.g. ITO) is patterned using techniques such as contact printing, lithography etc. The second electrode layer (eg Pt) and the metal oxide layer (eg TiO2) are both patterned using a mask.